Unknown user
I have two emails of unknown users on my Apple TV. I was able to delete one account but the second keeps popping up to enter the password but I can’t find it on the user page to delete it.
Question marked as
Possibly you have apps installed that were purchased using one of the other accounts. That would cause it to connect to the App Store periodically, thus requesting authentication for that account.
To completely remove previous accounts, reset your device to factory settings first. Reset or restore your Apple TV to its factory settings - Apple Support